Sabbath are riding high in charts across the world with the release of new work 13, which gave them a new world record when it made Number One in the UK, and his since given them their first-ever Number One album in the US.

Asked what happens after the band complete their touring schedule for 2013, including a set of UK dates in December, Ozzy tells the Telegraph: "It depends on Tony. At the moment we're doing so many weeks on the road, then he has to go back for more treatment.